Two men arrested in connection with the attempted murder of a police officer in North Belfast on Sunday have been released unconditionally.

A 36-year-old man and a 39-year-old man were released by police shortly after 7pm yesterday.

A 30-year-old man arrested on Monday remains in custody, assisting police with their enquiries

On Sunday, a police officer in his twenties was shot in a suspected dissident gun attack at a filling station forecourt on the Crumlin Road.

The officer was shot in the arm and it's understood he may have escaped more serious injury thanks to his protective vest.

Yesterday the officer was transferred from the Royal Victoria in Belfast to another hospital and is understood to be recovering well.

Police have appealed for witnesses and information on a red Audi A4 Estate, registration number KNZ 2862, which they believe was used by the attackers to leave the scene following the shooting.

Speaking just hours after the attack on Sunday, the Assistant Chief Constable Mark Hamilton described the attack as "reckless madness".

ACC Hamilton commended the petrol station customers who came to the injured officer's aid, despite their own lives being at risk.

"This was a very concerted attack on officers, this was a very concerted attempt to murder them and our main line of enquiry is violent dissident republicans," he said.

The Chief Constable, George Hamilton, visited the injured officer and said it was "very fortunate" he was not making an appeal for a murder investigation.

"The officer appears to have been struck three times on the right arm, causing fairly significant damage. He was in theatre for over three hours and will have further surgery in the days ahead," he said.

"He is in good spirits. I never cease to be amazed by the bravery and professionalism of police officers like him that I come across on a daily basis.

"We, as police officers, are citizens in uniform.

"This officer was a member of the community.

"He was attacked but actually, other members of the community were put at massive risk as well. The people who did this did not care who they murdered - albeit it's clear this attack was aimed at the police officer on duty."

DUP leader and former First Minister Arlene Foster said the attack was "a reminder of the threat which still exists in our society".

Sinn Fein MLA for North Belfast Gerry Kelly also added his condemnation.

"I hope that the injured officer will make a full and speedy recovery," he said.

"Those responsible for this attack are the same people who are attacking the local community. They have absolutely nothing to offer society and need to call a halt to these activities immediately."